A known rotation detecting device including magnetic detecting element for detecting the rotating condition of a rotor is disclosed in Japanese Patent Laid-Open Publication published as H11(1999)-64363. A first magnetic detecting element and a second magnetic detecting element are provided opposed to the rotor, and a signal processing device generates pulse signal being synchronized with the rotating condition of the rotor for indicating positive or reverse condition of the rotation of the rotor based on rotation signals generated by the first magnetic detecting element and the second magnetic detecting elements. The signal processing device generates the pulse signal with different pulse widths to distinguish between the case where the first magnetic detecting element generates the rotation signal prior to the first magnetic detecting element and the case where the second magnetic detecting element generates the rotation signal prior to the first magnetic detecting element, so that the rotating condition of the rotor, rotating in the positive direction or the reverse direction, can be specified based on such pulse signals.
Such rotation detecting devices, for example, may be provided at rotation speed sensor on both left and right side of the vehicle opposed to the rotors being made of magnetic material and rotating integrally with vehicle wheels for detecting the rotating speeds of the vehicle wheels.
The rotation detecting devices detect the rotating directions of the vehicle wheels on both right and left side of the vehicle in vehicle width direction, however, the signal generated from either one of the rotation detecting devices for indicating a rotating direction results in indicating the opposite direction because such devices provided on both right and left side of the vehicle in vehicle width direction are not symmetrical configuration. As a result, the pulse signal indicating the positive rotation or the reverse rotation (e.g. forward movement or reverse movement of the vehicle) results in being reversed. To solve aforementioned problems, a rotation detecting device having a configuration for outputting an opposite pulse signal needs to be provided, however, it drives the cost of the vehicle way up.
The present invention therefore takes account the aforementioned problems and seeks to provide a device for switching the pulse output between a positive condition and a reverse condition. In addition, the present invention also seeks to provide a device which can be used commonly on left, right, upper and lower sides of the vehicle.